1. Field of the Invention
The present invention generally relates to portable data processing devices, and particularly to a portable data processing device capable of transmitting processed data with a radio under low power consumption. The present invention has particular applicability to a small size data processing device which is called "an electronic organizer".
2. Description of the Background Art
With development of larger scale integration of semiconductor devices, electronic equipments employing semiconductor devices have been more and more miniaturized recently. A portable computer includes various semiconductor devices of which sizes are made smaller and smaller with a higher scale of integration of the semiconductor devices and improvement of functions. Generally, well known portable computers include laptop personal computers, note type personal computers and small size data processing devices or portable personal computers which are called "electronic organizers". The present invention is generally applicable to the above-mentioned portable computers, but a case where the present invention is applied to the above-mentioned "electronic organizer" will be described in the description below.
In the electronic organizer, various functions such as a telephone book, schedule, watch, world watch, calendar, desk-top calculator, simple table calculation and memorandum are provided in a device of a pocket notebook size, which is very light weight and convenient for carrying around. Accordingly, a user can store data such as a list of clients, a schedule, names of products and a price list in the electronic organizer. When a contract is made outside the office, data related to the contract is inputted into the organizer. After the user comes back to the office, the stored contract data is transferred from the electronic organizer to a host computer through a communication function. The data for manufacturing is thus supplied to a manufacturing division through the host computer. In this way, the data management from manufacture to sales is extremely facilitated. Especially, various IC cards which can be exchanges have been developed recently, so that the electronic organizers are increasingly used for various purposes.
FIG. 10 is a block diagram of a conventional electronic organizer. Referring to FIG. 10, the electronic organizer includes a main body 3 of the electronic organizer, and an exchangeable IC card 4a employed with it. The electronic organizer main body 3 includes a controller 301, a memory 302, a display 303, an input key 304, and input/output (I/0) terminals or connectors 305 and 306. The IC card 4a includes a memory 401, and an I/O terminal 402. Various commands and data processed in electronic organizer main body 3 are supplied through input key 304 and processed in controller 301. The processed data is supplied to memory 302 and display 303. Programs for operational processings and inputted data are stored in memory 302. An inexpensive liquid crystal display is employed as display 303.
When IC card 4a is used, input/output terminal 305 of main body 3 and input/output terminal 402 of IC card 4a are connected to each other. Memory 401 of IC card 4a is formed of a read only memory (ROM), where programs for operational processings and data are stored. Main body 3 of electronic organizer 3 employs the programs and data through terminals 305 and 402. Such data stored in IC card 4a includes English-Japanese dictionary data, Japanese-English dictionary data, game software and the like. On the other hand, separately from the same, there is an IC card 4b shown in FIG. 11. The IC card 4b includes a memory 401, an I/O terminal 402, a rewritable memory 403 and a battery 404 as a DC power supply. Accordingly, the IC card 4b is suitable for handling a large amount of data such as address book data.
Programs and data are stored in memories 401 and IC cards 4a and 4b depending on the purposes, so that a single electronic organizer can be utilized for various purposes by exchanging IC cards. Furthermore, main body 3 of the electronic organizer has I/O terminal 306 in which data can be shared with a personal computer by connected an external equipment thereto, e.g., a personal computer. That is, the data stored in the electronic organizer is transmitted to the personal computer, where desired data processings are performed. The processed data is stored in a flexible disk. On the other hand, the data in the flexible disk also can be transmitted to the electronic organizer. Generally, data input through an input key provided in an input portion 304 of main body 3 of an electronic organizer takes a long time, so that data inputted through a personal computer are often transferred to the electronic organizer via a communication function. In this way, the application range of electronic organizers is very wide.
On the other hand, radio communication for the purpose of use in relatively short distances such as inside a factory of an office has increased. Typical examples of such radio communication equipment also include the private paging system and the low speed data transmission system. The private paging system includes an input device having a personal computer and the like, a base station and a branch station. In this system, a call transmission of character/voice information and the like are made by the radio communication from the base station to a portable receiver (branch station). The character/voice information is transmitted with a digital signal and displayed on a display of the portable receiver.
FIG. 12 is a block diagram of a portable receiver (branch station) of the conventional private paging system. Referring to FIG. 12, portable receiver 7 includes an antenna 71, a receiver 72, an oscillator 73 and a controller 74. A signal transmitted from the base station is received through antenna 71 and supplied to a first mixer 721 together with a signal produced from a local oscillator in oscillator 73. A first intermediate frequency signal (referred to as a "IF signal", hereinafter) obtained in mixer 721 is amplified by a first IF amplifier 722 and then supplied to a second mixer 723. A second IF signal obtained in the second mixer 723 is amplified by a second IF amplifier 724 and then demodulated into a digital signal by a demodulator 725. The demodulated data is supplied to a CPU 741, where operational processings are applied thereto. The processed data is displayed on display 743 and also stored in memory 742. Memory 742 stores a program and received data. Functions such as selection call, group call, and simulcast call etc. are provided for as calling functions of the branch station, with which, in hospitals, hotels, offices and so forth, doctors, nurses and workers, for example, are called or, information are transmitted to them.
On the other hand, the low speed data transmitting system includes a data terminal device such as a personal computer, a base station and a branch station. In this system, data of an office automation (OA) terminal such as a personal computer is bilaterally transmitted via radio at a transmission speed of 4800 bps or less. It can be used for purposes such as real time entry of data such as takings and orders in a store and management of stocks in a warehouse.
FIG. 13 is a block diagram of a branch station in the conventional low speed data transmission system. Referring to FIG. 13, a branch station 8 includes an antenna 81, a receiver 82, an oscillator 83, a controller 84, a transmitter 85 and a data input 86. In the description below, a case where the system is applied to ordering work in a restaurant will be described. When a customer orders a dish, the information is transmitted to a base station provided in a kitchen. That is, the data of ordering information (e.g., a name of the dish, the number of dishes, a table number) is inputted through data input 86. The data is subjected to operational processes in CPU 841. The inputted data is displayed in display 842 for confirmation. Next, the carrier sensing (carrier detection) is performed to detect a free channel. When a free channel is detected, the oscillating frequency of a local oscillator 832 is controlled so that a carrier of that frequency is generated. The carrier produced from local oscillator 832 is supplied to modulator 851 through a high frequency switch 831 switched to the transmitter 85 side. A modulation signal corresponding to data to be transmitted is applied to modulator 851 from CPU 841, and the carrier is modulated in response to the modulation signal. The power of the modulated signal is amplified by power amplifier 852. Then, an antenna switch 813 is on the transmitter 85 side. The amplified transmission signal, from which unnecessary signal components are removed by a bandpass filter 812, is transmitted toward the base station through antenna 811.
The base station receives the data transmitted from the branch station to provide a cook with ordering information by, for example, displaying the data on a CRT of a personal computer, or by outputting the data with a printer.
On the contrary, when the branch station receives information (how far the cooking has progressed) from the base station, a signal transmitted from the base station is received by antenna 811 and unnecessary signal components are removed by bandpass filter 812. The antenna switch 813 is on the receiver 82 side, so that the received signal is amplified by high frequency amplifier 821 and then supplied to first mixer 822. The high frequency switch 831 is on the receiver 82 side, so that a local oscillator signal produced from local oscillator 832 is also supplied to the first mixer 822. A first IF signal obtained by mixing in the first mixer 822 is amplified by a first IF amplifier 823 and then supplied to a second mixer 824. A second IF signal obtained in second mixer 824 is amplified by second IF amplifier 825 and then demodulated into a digital signal by demodulator 826. The demodulated data is supplied to CPU 841, where operational processings are performed thereto. The operationally processed data are displayed on display 842 and also stored in memory 843. The system can be also utilized as a radio modem having transmission speed of 4800 bps other than utilization in the ordering work in a family restaurant as described above.
As described above, although a conventional electronic organizer has a wide application range, an IC card cannot be used when it is separated from the electronic organizer main body. In addition, transmission/reception of data from and to the electronic organizer main body has to be necessarily made through communication I/O terminals.
As an example of transmitting/receiving data during travel for the above-described private paging system, a low speed data transmission system or the like are known, but the former has disadvantage that the data cannot be transmitted to the host computer side during travel since it is unilateral communication from the base station to the branch station. In addition, both of the systems have complicated circuit structure and the mobile station (a branch station) is provided with a local oscillator, resulting in an increase in consumption power. Accordingly, a considerably large battery is required for long time use, which has been an obstacle to miniaturization as well as an increase in weight. This also makes it impossible to provide a radio function to an IC card of an electronic organizer which is extremely small and light.